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| author | Joel Stanley <joel@jms.id.au> | 2021-12-07 14:08:10 +1030 |
|---|---|---|
| committer | Joel Stanley <joel@jms.id.au> | 2022-01-31 15:56:55 +1030 |
| commit | d46fddd52d11eb6a3a7ed836f9f273e9cf8cd01c (patch) | |
| tree | ebf8a1a959d6b82ab705ea188eb34f2bc16b3ce7 /drivers/fsi | |
| parent | e783362eb54cd99b2cac8b3a9aeac942e6f6ac07 (diff) | |
| download | lwn-d46fddd52d11eb6a3a7ed836f9f273e9cf8cd01c.tar.gz lwn-d46fddd52d11eb6a3a7ed836f9f273e9cf8cd01c.zip | |
fsi: scom: Fix error handling
SCOM error handling is made complex by trying to pass around two bits of
information: the function return code, and a status parameter that
represents the CFAM error status register.
The commit f72ddbe1d7b7 ("fsi: scom: Remove retries") removed the
"hidden" retries in the SCOM driver, in preference of allowing the
calling code (userspace or driver) to decide how to handle a failed
SCOM. However it introduced a bug by attempting to be smart about the
return codes that were "errors" and which were ok to fall through to the
status register parsing.
We get the following errors:
- EINVAL or ENXIO, for indirect scoms where the value is invalid
- EINVAL, where the size or address is incorrect
- EIO or ETIMEOUT, where FSI write failed (aspeed master)
- EAGAIN, where the master detected a crc error (GPIO master only)
- EBUSY, where the bus is disabled (GPIO master in external mode)
In all of these cases we should fail the SCOM read/write and return the
error.
Thanks to Dan Carpenter for the detailed bug report.
Fixes: f72ddbe1d7b7 ("fsi: scom: Remove retries")
Link: https://lists.ozlabs.org/pipermail/linux-fsi/2021-November/000235.html
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20211207033811.518981-2-joel@jms.id.au
Signed-off-by: Joel Stanley <joel@jms.id.au>
Diffstat (limited to 'drivers/fsi')
| -rw-r--r-- | drivers/fsi/fsi-scom.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/fsi/fsi-scom.c b/drivers/fsi/fsi-scom.c index da1486bb6a14..3b427f7e9027 100644 --- a/drivers/fsi/fsi-scom.c +++ b/drivers/fsi/fsi-scom.c @@ -289,7 +289,7 @@ static int put_scom(struct scom_device *scom, uint64_t value, int rc; rc = raw_put_scom(scom, value, addr, &status); - if (rc == -ENODEV) + if (rc) return rc; rc = handle_fsi2pib_status(scom, status); @@ -308,7 +308,7 @@ static int get_scom(struct scom_device *scom, uint64_t *value, int rc; rc = raw_get_scom(scom, value, addr, &status); - if (rc == -ENODEV) + if (rc) return rc; rc = handle_fsi2pib_status(scom, status); |